This invention relates to friction torque transmitting devices and more particularly to such devices having multiple discs and variable capacity.
Multiple disc friction torque transmitting devices providing variable capacity engagement are used to establish a smooth shift characteristic in power transmissions. These devices generally rely on a precise hydraulic pressure control to produce the desired engagement characteristic. Therefore, the smoothness of the shift or engagement of the friction device is subject to the temperature characteristics of the hydraulic fluid as well as fluid leakage that might occur in the hydraulic control circuit.
These problems have been addressed in the prior art by providing hydraulic timing circuits utilizing such devices as accumulators and one or more flow restrictors, or in some instances, a temperature compensating valve.